package com.排序.排序基础;

public class 归并排序 {

    public static void merge(int[] a1, int i, int iEnd, int j, int jEnd, int[] a2){
        int k = i;
        while (i <= iEnd && j <= jEnd){
            if(a1[i] <= a1[j]){
                a2[k] = a1[i];
                i++;
            }else {
                a2[k] = a1[j];
                j++;
            }
            k++;
        }
    }
    public static void sort(int[] a1){
        int[] a2=new int[a1.length];
        split(a1,0,a1.length-1,a2);
    }

    private static void split(int[] a1, int left, int right, int[] a2){
        if(left == right){
            return;
        }

        int m = (left+right) >>> 1;
        split(a1, left, m, a2);
        split(a1, m+1, right, a2);

        merge(a1, left, m, m + 1, right, a2);
    }

}
